Improvement in hoisting apparatus



UNITED STATES PATENT OFFICE;

JOSEPI TALPEY, 0F SOMERVILLE, MASSACHUSETTS.

AIMPROVEMENT lN HOISTING APPARATUS.

Specification ibi-ming part ot Letters Patent No. i 7,878, dated May 2li, 1865.

To all whom it may concern:

Be it known that I, J osEPH A, TALPEY, of Somerville, in the county of Middlesex and State ot' ll'lassachnsetts, have invented 1inproved Tackle or Hoistin g Apparat-us; and I do hereby declare that the following, taken in connection with the drawings, which accompany and form part of this specification, is a description of my invention sufficient to enable those skilled in the art to practice it.

This invention relates tothe employment of hoisting-tackle t'or raising and lowering heavy bodies, the object of the invention being to aftorda ready means in such apparatus for holding the body in suspension at any point without necessity of belaying the slack of the pulley chain or rope. Hoisting apparatus for this purpose has already been made and used, the saine consisting of two sprocketwheels or pulleys of unequal diameter, fixed on the saine shaft and integral with eachother, or moving as one wheel in the block, andA an endless chain, working in connection with the teeth of the two sprocket-pulleys. v

lvl y improvement consists in the employ nient, in connection with an endless chain, of

two separate sprocket-wheels geared together,

the proportion of `the respective diameter of the gear and sprpcketwheel ot' one shaft varying slightly from that of the'gear and sprocket upon the other shalt; also in soapplyiug the lower sprocket-wheel that it can be thrown out ot' connection with the uppei` one and locked in position to prevent its rotation, thus permitting the chain to be overhauled upon the upper sprocket, which acts as a simple pulley.

Figures l and 2 oil the drawings represent, respectively, a side and front elevation of a tackle or hoisting apparatus embodying my improvement.

a denotes the upper or stationary block, ca rryin g a pulley or sprocketwheel, b,hav1ng a gear-wheel, c, integral with or fixed to one or both sides of it, as seen in Fig. 2, the space between the gears serving as a guide-groove to the endlesschain d, which passes over it, as will be readily understood. 'lhe gearor gears c mesh into another gear or gears, c, inountedin the shell ot the block a, and below .the gears c, said gear or gears e being tixed upon one or both sides of a pulley or sprocketwheel, lhe endless chain .1 passes overthe the lower on'e.

pulley j" i'rom the same side of the block that it passes over the other pulley b, and there is hung or suspended to the 'chain upon one side ofthe block a a block, 11, carrying a loose pulley,- h, around which the cha-in traverses. Supposing the upper block to be stationary and a weight to be suspended l'rom the lower block, it will be obvious that, il' the diameter of the sprocketfwheel b bears the samepro portion to the diameter of the gear or gears to which it is iixed, the diameter ol' the sprocket-wheel or pulley j' hears to its gear, that overhauling the chain would Vproduce neither rise nor descent of the block l1 or the weight suspended therefrom. li', however, this proportion is varied, then overhauling the chain will produce the rise or fall of the weight sprocket-wheel to contain twenty teeth' and the lower gear to behalf the size ot' the upper one. Now, it', instead of making the lower sprocket-wheel with ten teeth, its diameter be decreased until nine teeth till its eircunif'er ence, the adjacent sprocketteeth in both wheels being ot' course cquidistant, it will be obvious that in hoisting by drawing upon the slack, as denoted by the arrow m, each revolution ot' the upper gear takes n p twenty links ot' the chain and lets ofi' eighteen from the lower wheel, thus gaining the length ot' two links at each revolution of the uppergear, while in lowering, drawing upon the slack,

vas denoted by the arrow s, the eieet is the opposite, twenty links being let oil' by the u1 )er wheel while but eighteen are taken up by Theoretically, et' course a weight hung upon the lower block would with such a construction cause the chain to overhaul of itself', butpractically, `with only a slight difference in the relation ot' the diameters as specified, very heavy bodies can be readily raised and lowered, and will be held in suspension at any point iu the operation without belaying or fastening the slack, the l'riction bein g-suliicient for this purpose.

I n machineshops, forges, and other places where heavy bodies are hoisted and inoved about for manipulation such lan apparatus is found very convenient and useful.

lly employing the separate sprocket-wheels geared together, as shown, instead ot' two spmeketu heels upon one shaft, the slack ot' the chain hangs upon the opposite side ot' the A as, for instance, suppose the upper' gears from that part ot' the chain to'which the weight is suspended without the use .of guidepulleys and without danger ot' causing interference ot' the slack with the other part ot' the chain. Moreover, the lower sprocket-pulley can be easily removed with its gear tor replacement, when advisable, by others having slightly-varying diameters 5 but, besides this, it is desirable to so construct the apparatusy that the chain can he overhauled upon one of A the sprockets as a simple pulley without the in the block between the two adjacent lower most teeth of the gear, thus locking the lower gearin position and lneventing its rotation.A

1t willnow be obvious that the chain may be overhauled upon the.r upper pulley in either direction' and' as fast as the pulley is rotated. Thisis desirable in raising and lowering the lower block to bring it to any (lesired position when there isno weight upon it, at which time it is ot course not necessary or desirable to compound the upper pulley with the lower one to increase the power, it being more desirable to 4Ireadily and quickly bring the lower block into position.

Instead ofthe construction described, there may be a slight difference made in the sizes of the teeth of the respective gears or i-n the distance apart ot' the sprocket-teeth upon the respective pulleys, but I consider the construction shown to be preferable.

I claiml. The improved tackle orhoisting apparatus, consisting ot' two sprocket-pulleys arv ranged, constructed, and geared togethenand operating i n conjunction with the endless chain and the loose block, substantially as specilied.

2. So applying the lower sprocketpulley that it may be disconnected from the upper one and keyed or fastened in position in the manner and for the purpose substantially as set forth.

In witness whereof I have hereunto set my hand this 19th day'of January, A. l). 1865.'

JSEPI-l A. TALPEY.

'FRANCIS GoULn, W. B. GLEAsoN. 

